1. Field of the Invention
The present invention relates to vehicle doorbeams, and more particularly to such doorbeams with reinforcing inserts.
2. Description of the Art
Vehicle doorbeams are widely used in the automotive industry to enhance the impact strength of vehicle doors and thereby enhance automobile safety. A doorbeam typically is roll-formed from steel and includes a hat-shaped beam portion and a pair of paddles at either end of the beam portion. A doorbeam typically is secured within a vehicle door by welding the paddles to the door frame.
When considering the design of doorbeamsxe2x80x94as well as virtually all automotive componentsxe2x80x94designers seek an appropriate balance among performance, weight, and cost. As part of that balance, it is known that the weight of a doorbeam can be decreased by manufacturing the doorbeam of a relatively expensive material. However, this undesirably increases the cost of the doorbeam. It also is known that the strength of a doorbeam can be increased by manufacturing the doorbeam from relatively thick stock. However, this undesirably increases the weight of the doorbeam.
In any effort to reduce overall weight, some designers include a reinforcing component on the hat-shaped beam. Examples of this approach are disclosed in U.S. Pat. No. 5,692,797 issued Dec. 2, 1997 to Dancasiu; U.S. Pat. No. 4,796,946 issued Jan. 10, 1989 to Wilson et al; and U.S. Pat. No. 4,684,166 issued Aug. 4, 1987 to Kanodia. In all of these designs, a relatively flat reinforcement is crimped onto a segment of the hat-shaped doorbeam. However, designers continue to seek additional improvements in the performance/weight/cost balance.
The aforementioned problems are overcome in the present application wherein a doorbeam includes a relatively high-strength, hat-shaped insert crimped into a relatively low-strength body. The assembly provides desired performance at relatively low weight and relatively low cost. In the preferred embodiment, the insert is fabricated of Martinsite; and the beam is fabricated of mild steel.
The present invention has a variety of advantages over prior techniques. First, the majority of the doorbeam is formed of a relatively inexpensive material. Second, the reinforcing insert provides the necessary impact strength only where needed, thereby decreasing the overall weight and cost of the doorbeam. Third, the beam is manufactured in a variety of lengths by changing only the length of the base member, and not necessarily the insert.
These and other objects, advantages and features of the invention will be more fully understood and appreciated by reference to the detailed description of the preferred embodiments and the drawings.